In this paper, we present a numerical simulation study of nitride-based p-i-n ultraviolet bandpass photodetectors, which was designed with a high Al composition AlGaN unipolar barrier layer. The AlGaN unipolar blocking layers act as potential barrier that reduce the collection of carriers generated by high energy photons in p-Al 0.1 Ga 0.9 N short-wave filter layer. Compared to the conventional nitride-based p-i-n band-pass photodiodes, this new structure devices are capable high short-wave rejection ration. To validate the model, we compared the simulation predictions with experimental data of conventional p-i-n bandpass photodiodes published in the literature. This concept can be applicable for any p-i-n photodetectors.